1. Field of the Invention
The invention relates to expandable rooms for habitable structures, especially room structures that are telescopically slideable between retracted and expanded positions for motorized or towed vehicles.
A variety of vehicles are known and used which have a room or room portion that may be moved from a retracted position nested within the vehicle body while the vehicle is moving over the road and then extended when the vehicle is stationary to provide additional internal space. This type of arrangement provides adequate space to accommodate users during transit and keeps the vehicle within regulations that impose width limitations for vehicles while traveling over the road. However, when these vehicles are stationary, they are frequently used for habitation for extended periods of time, and when so used, it is highly desirable to be able to maximize the available living space. Typically, this is done by using hydraulic or electrical power to extend the nested portion of the room out to its expanded position.
2. Description of the Prior Art
The prior art teaches arrangements which allow the floor sections of the vehicle and the extendable room to be at the same height when the room is in its extended position. When in the fully retracted position, the floor of the movable room rests on the stationary floor of the vehicle. One or more extension cylinders are positioned beneath the floor of the vehicle, each extension cylinder powering a double tube arrangement supported by the structural members of the vehicle, with an inner tube connected to the extendable room. When the room is to be extended, the inner tube advanced under power of the extension cylinders moving the room outwardly while maintaining the floor at the same level above the stationary floor of the vehicle. As the inner end of the extendable room approaches its fully extended position, it moves downwardly to its fully extended position with the floor of the extendable room is at the same level as the stationary floor of the vehicle. The extension components are provided with a ramp arrangement to compensate for the drop of the room. An arrangement of such a prior art apparatus is shown in U.S. Pat. No. 6,052,952 entitled xe2x80x9cFlat Floor Room Extensionxe2x80x9d.
In addition to the arrangement just described, there are known vehicles which use a double tube arrangement for extending and retracting the expandable room but which do not utilize a ramp arrangement for the extension mechanism. Rather, the inner tube that is telescoped within the outer tube has its outer end attached rigidly to the outer wall of the extendable room, and without any mechanism to compensate for the drop of the room, the structural components will flex sufficiently to compensate for the drop. Although these arrangements are less costly and take up less space because of the elimination of a ramping mechanism, they depend upon the flexibility of the various components to compensate for the drop and rise of the extendable room. Thus, when the room moves from a retracted to an extended position and from the extended position to a fully retracted position, undesirable stress is exerted on the structural components including the connection between the inner tube and the outer wall of the extendable room. Repeated extensions and retractions of the room can therefore produce some deformation of the components and cause misalignment of the room when fully retracted.
It is therefore an object of the invention to provide an improved structure which will provide for a mechanism for extendable rooms that will minimize forces and stresses on the structures involved while still providing a relatively inexpensive structure that requires a minimum of space.
The invention includes telescoping double tube extension beams that are secured to the vehicle structure and combined with hydraulic extension cylinders to move the extendable room from the retracted to the extended position and back again. The hydraulic cylinders are mounted inside the extension beams, one end to the outer tube of the extension beam and the other end to the inner tube of the extension beam. The inner tube is connected to the outer wall of the extendable room using a pivot connector that includes a mounting plate which has extending from it spaced apart support plates that provide bearing surfaces to support a journal. The journal has a transverse opening extending through it between the support plates, and a connecting member is used to attach the inner tube to the journal and therefore to room mounting plate, the connecting member also serving to retain the journal in place between the supporting plates.